Multifunctional additive compositions enabling middle distillates to be operable in cold conditions

ABSTRACT

The invention concerns a multifunctional additive enabling fuels to be operable in cold conditions, consisting of copolymers of at least a dicarboxylic compound with at least an olefin, and whereon are grafted nitrogenous functions and/or esters of general formula (I) wherein: R 1  and R 2 , and R 4  and R 5 , R 3  and R 6  are hydrogen or alkyl radicals, and x is selected among the amine salts and N-alkylpolyalkylenepolyamines and their monohydroxylated and polyhydroxylated derivatives, N-alkylpolyalkylenepolyamine alkylesters and esters, and alkylamines and N-alkylpolyalkylenepolyamines.

[0001] The present invention concerns a novel multifunctional additivethat improves the operability of middle distillates in cold conditions Aparticular aim is the improvement of the dispersing andanti-sedimentation properties and the lowering of the pour point andcloud point temperatures, but also an improvement in the cetane numberof these distillates for use as a fuel in diesel engines and in fuelssuch as domestic fuel oil for boilers.

[0002] Cold operability corresponds to a limiting temperature at whichthe middle distillates may be used without problems of dogging. It liesbetween the cloud point temperature (ASTM D 2500-98) that characterisesthe onset of crystallisation of paraffins in the distillate and the pourpoint of the distillate (ASTM D 97-96a).

[0003] It is well known that the crystallisation of paraffins is alimiting factor in the use of middle distillates. Thus, it is importantto prepare diesel fuels that are adapted to the temperatures at whichthey will be used in automotive vehicles, in other words the ambientconditions. Generally, cold operability of fuels at −10° C. issufficient in many industrialised countries. However, in othercountries, such as northern countries, Canada and the countries ofnorthern Asia, fuels can be used at temperatures less than −20° C. Thesame is true for domestic fuel oils stored outside for individual housesand blocks of Flats.

[0004] This cold operability suitability of diesel fuels is important,especially when engines are started up from cold. If the paraffinscrystallise at the bottom of the fuel tank, they can be drawn into thefuel circuit on start up and clog in particular the filters andpre-filters located upstream of the injection systems (pump andinjectors). The same holds for the storage of domestic fuel oils;paraffins precipitate at the bottom of the tank and may be drawn intoand obstruct the pipes upstream of the pump and the boiler feed system(jet and filter). It is obvious that the presence of solids, such asparaffin crystals, prevents the normal circulation of the middledistillate.

[0005] In order to improve their circulation either in the engine, ortowards the boilers, several types of additive have been developed.

[0006] First of all, the oil industry concentrated on developingadditives that favour the filterability of fuels at low temperatures.The role of these additives, called CFPP (cold filter plugging point)additives, is to limit the size of the paraffin crystals that areformed.

[0007] This type of additive, very widely known to those skilled in theart, is presently added systematically to middle distillates.

[0008] However these additives, although they regulate the size of theparaffin crystals, cannot prevent the sedimentation of the crystalsformed, in other words their agglomeration, especially at the bottom ofthe fuel tanks in diesel vehicles when at rest or in the storage tanksof domestic fuel oils.

[0009] Thus, at a later stage, the oil industry did its best to developanti-sedimentation additives, in other words dispersants, which maintainthe paraffin crystals in suspension in the middle distillate, whichavoids them depositing or agglomerating with each other. The applicanthas, in particular, developed such an additive, described in patent EP 0674 698.

[0010] Nevertheless, the combined action of CFPP and anti-sedimentationadditives has not made it possible to improve the cold operability ofall middle distillates produced in refineries from all known crude oils.

[0011] This is why the oil industry has developed a third type ofadditive with a view to lowering the cold operability temperature ofmiddle distillates, whatever their type, including below −20 TC, even iftheir cloud point temperature is above −20° C. This is the case of theadditives described in patents EP 0 722 481 and EP 0 832 172.

[0012] The aim of the present invention is a novel multifunctionaladditive that enables the cold operability temperature to be lowered andmaintained down to temperatures below −20° C., and also to increase thecetane number of these distillates, without any sedimentation of theparaffins contained within the middle distillates.

[0013] The aim of the present invention is thus a multifunctionaladditive enabling fuels to be operable in cold conditions, consisting ofcopolymers with at least a dicarboxylic unit with at least an olefinunit and whereon are grafted nitrogenous functions and/or esters ofgeneral formula (I) hereafter:

[0014] Wherein: R₁ and R₂, identical or different, are hydrogen or alkylradicals containing from 1 to 20 carbon atoms, R₃ and R₆ are hydrogen oralkyl radicals containing from 1 to 30 carbon atoms, where R₃ isselected among alkyl groups containing from 10 to 30 carbon atoms whenR₆ is hydrogen and vice versa, R₄ and R₅, identical or different, arehydrogen or an alkyl group containing 1 to 22 carbon atoms, n and m arewhole numbers varying between 1 and 50, and X is selected among:

[0015] i) amine salts of the type

[0016] wherein R′¹ and R′₂, identical or different, are selected amongalkyl groups containing from 1 to 18 carbon atoms, alkylaminescontaining from 1 to 18 carbon atoms, N-alkylpolyalkylene-polyamines offormula (II):

[0017] wherein R′₃ and R′₄, identical or different, are hydrogen or alinear or branched alkyl group containing from 1 to 22 carbon atoms, andx, y and z are whole numbers, x varying between 1 and 6 and y and zvarying between 0 and 6, and mono and poly-hydroxylated amines andpolyamines.

[0018] ii) esters —OR's, R′₅ selected among alkyl radicals containingfrom 1 to 30 carbon atoms and N-alkylpolyalkylene-polyamines of formula(II).

[0019] iii) and alkylamines containing from 1 to 44 carbon atoms andN-alkylpolyalkylene-polyamines of formula (II).

[0020] It has been observed that these multifunctional additives, whenused alone or in mixtures, have, in an unexpected manner, both betterdispersion properties and anti-sedimentation properties than knownmultifunctional additives for cold operability, a lowering of the pourpoint and also a lowering of the filterability temperature (or CFPP) andthe cloud point of fuels, as well as an improvement in the cetanenumber.

[0021] According to the present invention, the copolymer of formula (I)is preferably a copolymer containing 45 to 65% mole of at least anolefin unit and 55 to 35% mole of at least a dicarboxylic unit. Thedicarboxylic units are preferably selected among the group comprisingmaleic anhydride, citraconic anhydride and fumaric acid, and the olefinunits selected among linear or branched alkenyl units containing from 1to 30 carbon atoms. In a preferred embodiment, the copolymer is selectedamong maleic anhydride-octadecene, maleic anhydride-dodecene and maleicanhydride-hexadecene.

[0022] In the copolymer of formula (I), R₁ and R₂ are radicalspreferably selected among the group comprising dodecyl and octadecylradicals and R₃ is selected among alkyl groups containing from 10 to 20carbon atoms.

[0023] A first additive according to the invention is the copolymer offormula (Ill) hereafter:

[0024] wherein R′₁ and R′₂, identical or different, are selected amongalkyl radicals containing from 12 to 18 carbon atoms, alkylaminescontaining from 1 to 22 carbon atoms and N-alkylpolyalkylene-polyaminesof formula (II) and hydroxylated amines from the group comprisingdiethanolamine, monoethanolamine, N-butylamine, N-decylethanolamine andN-dodecylethanolamine and their alkoxylated derivatives.

[0025] and R′₃ is selected among decyl, tetradecyl, hexadecyl, octadecyland eicosyl radicals.

[0026] A second additive according to the invention is the copolymer offormula (IV) hereafter

[0027] wherein:

[0028] R′₁ and R′₂, identical or different, are selected among alkylradicals containing from 1 to 22 carbon atoms andN-alkylpolyalkylene-polyamines from the group comprisingN-alkyldiethylene-triamines, N-alkyldipropylene-triamines,N-alkyltriethylene-tetramines, N-alkyltetraethylene-pentamines andN-alkyltetrapolypropylene-pentamines

[0029] and R′₃ is selected among decyl, tetradecyl, hexadecyl, octadecyland eicosyl radicals.

[0030] A third additive according to the invention is a copolymer offormula (V) hereafter:

[0031] wherein:

[0032] R′₅ is selected among alkyl radicals containing from 6 to 18carbon atoms and N-alkylpolyalkylene-polyamines of formula (II) from thegroup comprising N-alkyldiethylene-triamines,N-alkyldipropylene-triamines, N-alkyltriethylene-tetramines,N-alkyltetraethylene-pentamines and N-alkyltetrapropylene-pentamines

[0033] and R′₃ is selected among decyl, tetradecyl, hexadecyl, octadecyland eicosyl radicals.

[0034] According to the invention, the alkylamines andpolyalkylene-polyamines of formula (II) are selected from the groupcomprising dibutylamine, didodecylamine, dioctadecylamine,N-alkylethylene-diamines, N-alkylpropylene-diamines,N-alkylbutylene-diamines, N-alkyldiethylenetriamines,N-alkyldipropylene-triamines, N-alkyldibutylene-triamines,N-alkyltriethylene-tetramines, N-alkyltripropylene-tetramines,N-alkyltributylene-tetramines, N-alkyltetraethylene-pentamines,N-alkyltetrapropylene-pentamines and N-alkyltributylene-pentamines withan alkyl radical containing from 12 to 22 carbon atoms, preferablyN-dodecyidipropylene-triamine, N-octadecyidipropylene-triamine,N-ctadecyidiethylene-triamine and N-docosyldiethylene-triamine.

[0035] A second aim of the invention is a composition of additivescomprising an additive of formula (I) and at least an additive selectedamong filterability additives and/or flow additives, cetane numberimprovement additives, catalytic combustion promoters and soot,detergents, lubricating additives, anti-wear additives, anti-foamingadditives, anti-corrosion additives and other additives or additivecompositions for improving the cloud point, the dispersion and thesedimentation of paraffins.

[0036] Among these additives, the following may be cited in particular:

[0037] a) cetane number improvement additives, particularly (but notImitatively) selected among alkyl nitrates, preferably 2-ethylhexylnitrate, aroyl peroxides, preferably benzyl peroxide, alkyl peroxides,preferably ter-butyl peroxide.

[0038] b) filterability additive, particularly (but not limitatively)selected among ethylene—vinyl acetate (EVA), ethylene—vinyl propionate(EVP), ethylene—vinyl ethanoate (EVE), ethylene—methyl methacrylate(EMMA) and ethylene alkyl fumarate copolymers. Examples of suchadditives are given in the following documents: EP-A-0187488,FR-A-2490669, EP-A-0722481 and EP-A-0832172.

[0039] c) anti-foaming additive, particularly (but not limitatively)selected among polysiloxanes, oxyalkylated polysiloxanes and the amidesof fatty acids from vegetable or animal oils. Examples of such additivesare given in the following documents: EP-A-0861182, EP-A-0663000 andEP-A-0736590.

[0040] d) detergent and/or anticorrosion additive, particularly (but notlimitatively) selected among the group comprising amines, succinimides,alkenyl succinimides, polyalkylamines, polyalkyl-polyamines andpolyetheramines. Examples of such additives are given in the followingdocuments: EP-A-0938535.

[0041] e) lubrifying or anti-wear additive, particularly (but notimitatively) selected among the group comprising fatty acids and theirester or amide derivatives, especially glycerol mono-oleate, and thederivatives of mono- and poly-cyclic carboxylic acids. Examples of suchadditives are given in the following documents: EP-A-0680506,EP-A-0860494, WO-A-9804656, EP-A-0915944, FR-A-2772783 and FR-A-2772784.

[0042] f) cloud point additive, particularly (but not limitatively)selected among the group comprising long chain/(meth)acrylicester/maleimide olefin terpolymers, and polymers of fumaric/maleic acidesters. Examples of such additives are given in the following documents:EP-A-0071513, EP-A-0100248, FR-A-2528051, FR-A-2528051, FR-A-2528423,EP-A-0 112195, EP-A-01 72758, EP-A-0271385 and EP-A-0291367.

[0043] g) anti-sedimentation additive, particularly (but notlimitatively) selected among the group comprising (meth)acrylicacid/alkyl (meth)acrylate copolymers modified by a polyamine, polyaminealkenylsuccinimides and derivatives of phthalamic acid and double chainfatty amines. Examples of such additives are given in the followingdocuments: EP-A-0261959, EP-A-00593331, EP-A-0674689, EP-A-0327423,EP-A-0512889 and EP-A-0832172.

[0044] h) multifunctional additive for cold operability selected amongthe group comprising olefin based polymers and alkenyl nitrate such asthose described in EP 0 573 490.

[0045] A third aim according to the invention is a combustible, fueland/or fuel oil containing a major part of a hydrocarbon base comprisingpetrols, middle distillates, synthetic fuels, animal or vegetable oils,esterified or not, and their mixtures, and a minor part, correspondingto 50 to 1000 ppm, of at least a multifunctional additive of formula(I). This additive may be present in the fuel or combustible with atleast an additive from the group comprising cetane number improvementadditives, catalytic combustion promoters and soot, detergents,lubricating additives, anti-wear additives, anti-foaming additives,anti-corrosion additives and other additives or additive compositionsfor improving the cloud point, the dispersion and the sedimentation ofparaffins.

[0046] The following examples are given to illustrate the advantages ofthe present invention and are in nowise limitative.

EXAMPLE 1

[0047] The purpose of the present example is to illustrate theefficiency of the additives according to the invention in terms offilterability and flow in order to demonstrate the intrinsic propertiesof additives of formula (III), (IV) and (V), when they are used alone orwhen they are used in formulation with other additives.

[0048] The additive (III), referred to hereafter as additive 1,comprises a copolymer containing maleic anhydride units and ocadeceneunits in a 1/1 molar ratio, wherein R₁, R₂, R′₁ and R′₂ are identicaland correspond to a dodecylamine radical.

[0049] The additive (IV), referred to hereafter as additive 2, comprisesa copolymer containing maleic anhydride units and octadecene units in a1/1 molar ratio, wherein R₁ and R′₁ are hydrogen atoms, R₂ is a butylradical and R′₂ is a dodecyl radical.

[0050] The additive (V), referred to hereafter as additive 3, comprisesa copolymer containing maleic anhydride units and octadecene units in a1/1 molar ratio, wherein RI is a hydrogen atom, R₂ is an ethylamineradical and R₂ is a hexadecyl radical.

[0051] The above copolymers are generally obtained by the chemicalmodification of an alpha-olefin/maleic anhydride type copolymer, thealpha-olefin here being octadecene.

[0052] The octadecene/maleic anhydride copolymer is synthesized insolution in a solvent that is preferably aromatic (for example tolueneor xylene). The length of the olefin chain varies between 13 and 30carbons, and this monomer is radically copolymerised (in a molar ratiovarying from 0.4 to 0.6) with maleic anhydride, in bulk or in solution.A peroxide, hydroperoxide or azonitrile type of initiator is generallyused to control the molecular weight of the polymer at a concentration,by weight, of 0.5 to 5% of the total weight of monomers. Initiation isachieved in a thermal manner and preferably at temperatures between 60and 140° C., and more precisely between 80 and 120° C. In order toobtain the amide, or amine salt, type of dicarboxylated structure, 2molar equivalents of amine are reacted with 1 molar equivalent ofanhydride, without raising the temperature too much so as not to obtainthe diamide structure. The reaction temperature may vary from 20° C. to90° C., and preferably from 40 to 80° C. In order to obtain the ester,an alcohol is subsequently made to react in comparable proportions.

[0053] Each additive was introduced into three different diesels withthe characteristics shown in Table 1 below. TABLE 1 PROPERTY Diesel 1Diesel 2 Diesel 3 Cloud point (° C.) −5 −3 −1 Cold filter plugging point(° C.) −6 −5 −2 Pour point (° C.) −12 −12 −9 Crystallisation temperature(° C.) −8.9 −5.60 −9.85 Percentage paraffin 14.8 11.5 10.8 Initialboiling point 168 178 176 Boiling point at 5% volume 186 200 201 Boilingpoint at 20% volume 212 220 222 Boiling point at 40% volume 248 253 256Boiling point at 60% volume 272 278 282 Boiling point at 80% volume 305310 314 Boiling point at 90% volume 340 362 356 Final boiling point 354370 363 Density at 15° C. 0.8355 0.8375 0.8483 Hash point 65 71 70Cetane number 48.9 50.9 47.8

[0054] The cold operability results obtained with functional additivesaccording to the invention when they are introduced at a level of 0.025%into the three diesels in Table (I) are given in Table (II) below. TABLEII Gain/non- Gain/non- CFPP doped PPT doped Sample (° C.) diesel (° C.)(° C.) diesel (° C.) Diesel 1 −6 — −12 — Diesel 1 + additive “1” −10 4−21 9 Diesel 1 + additive “2” −10 4 −21 9 Diesel 1 + additive “3” −7 1−18 6 Diesel 2 −5 — −12 — Diesel 2 + additive “1” −18 13 −24 12 Diesel2 + additive “2” −18 13 −24 12 Diesel 2 + additive “3” −14 9 −27 15Diesel 3 −2 — −9 — Diesel 3 + additive “1” −16 14 −21 12

[0055] It can be seen from this table that whatever the additive 1, 2 or3, one observes a systematic gain in the pour point temperature (PPT)whatever the diesel, and that the increase in the cold filter pluggingpoint (CFPP) is especially marked in diesels 2 and 3.

[0056] Table (III) below shows the corresponding results of using thesethree additives in the same diesels but at a concentration of 0.0125% byweight, in combination with two filterability additives (FI₁ and FI₂)conventionally used for improving cold behaviour. These additives FI₁and FI₂ are copolymers or mixtures of copolymers of the ethylene/vinylacetate type, generally with a molecular weight varying between 5000 and50 000 and in which the level of vinyl acetate varies from 25% to 32% byweight. TABLE III Gain/non- Gain/non- CFPP doped PPT doped Sample (° C.)diesel (° C.) (° C.) diesel (° C.) Diesel 1 −6 — −12 — Diesel 1 + Fl₁−11 5 −21 9 Diesel 1 + Fl₂ −15 9 −21 9 Diesel 1 + Fl₁ + additive “1 ” 1711 −24 12 Diesel 1 + Fl₂ + additive “2” −20 14 −24 12 Diesel 1 + Fl₂ +additive “3” −18 12 −24 12 Diesel 2 −5 — −12 — Diesel 2 + Fl₁ −8 3 −21 9Diesel 2 + Fl₂ −12 7 −21 9 Diesel 2 + Fl₁ + additive “1” −16 11 −27 15Diesel 2 + Fl₂ + additive “2” −16 11 −30 18 Diesel 2 + Fl₂ + additive“3” −16 11 −27 15 Diesel 3 −2 — −9 — Diesel 3 + Fl₁ −12 10 −18 9 Diesel3 + Fl₁ + additive “1” −17 15 −24 15

[0057] It can be seen from this table and the previous table that theadditives according to the invention lead to a higher gain in the pourpoint than known FI additives. This gain is increased when additives 1,2 and 3 are combined with one of the FI additives.

EXAMPLE 2

[0058] This example shows the anti-sedimentation properties of additivesof formula (III), (IV) and (V) described in example 1 when they areintroduced alone into the three diesels 1, 2 and 3 at a level of 0.025%by weight or in combination with two additives FI_(I) and FI₂ at aconcentration of 0.0125% by weight for each additive.

[0059] The efficiency of these additives is determined by applying theNF M07-085 (95) Standard and assigning a rating for the CFPP and theonset of crystallisation temperature (OCT). The results are shown inTable IV below. TABLE IV Sedimentation (NF M07-085 (95) Standard) DeltaDelta Visual OCT CFPP Sample reading (° C.) (° C.) “Zone” Diesel 1 6O +C 22.5 17 C Diesel 1 + additive “1” cloudy 3.2 2 A Diesel 1 + Fl₁ 58 + C22.8 18 C Diesel 1 + Fl₁ + additive “1” 114 + cloudy 16.4 4 B Diesel 264 + C 24.2 19 C Diesel 2 + additive “1” Cloudy 6.1 5 A Diesel2 + Fl₁66 + C 21.0 19 C Diesel 2 + Fl₁ + additive “1” 187 + C 17.8 6 B Diesel 358 + 0 23.4 19 C Diesel 3 + additive “1” 232 + cloudy 8.5 5 A Diesel 3 +Fl₁ 58 + C 23.0 19 C Diesel 3 + Fl₁ + additive “1” 136 + cloudy 10.7 6 ADiesel 1 + additive “2” Cloudy 5.5 5 A Diesel 1 + Fl₂ 58 + 0 22.8 18 CDiesel 1 + Fl₂ + additive “2” 150 + C 15.1 9 B Diesel 2 + additive “2”162 + C 11.2 8 B Diesel 2 + Fl₂ 66 + C 21.0 19 C Diesel 2 + Fl₂ +additive “2” 168 + C 9.7 10 B Diesel 1 + additive “3” 236 + C 4.3 5 ADiesel 1 + Fl₂ + additive “3” 164 + cloudy 10.2 13 B Diesel 2 + additive“3” 172 + C 14.1 10 B Diesel 2 + Fl₂ + additive “3” 198 + c 15.3 8 B

[0060] In this table, A corresponds to very little sedimentation, B tostability and C to a heavy sedimentation, visible to the naked eye.

[0061] From the results shown in this table, one can conclude that theadditives 1, 2 and 3 provide an anti-sedimentation effect, reflected bya change in the assigned rating (C into A or C into B), whether they areused alone or in a mixture in each of the diesels in the presence of anFl additive.

EXAMPLE 3

[0062] The present example illustrates the ability of the additives 1, 2and 3 of the invention to lower the cloud point of diesels, whereby thiscloud point corresponds to the onset of crystallisation temperature(OCT), determined according to the IP 389/90 Standard. TABLE V SampleOCT (° C.) Diesel 1 −8.6 Diesel 1 + additive “1” −9.7 Diesel 1 +additive “2” −10.0 Diesel 2 −4.1 Diesel 2 + additive “1” −5.3 Diesel 2 +additive “2” −5.2

[0063] It can be seen from this table that additives 1, 2 and 3 favourthe lowering of the onset of crystallisation temperature (OCT) by atleast 1° C., which represents, for those skilled in the art, anappreciable gain.

EXAMPLE 4

[0064] The present example illustrates the cetane number improvementeffect provided by the additive of formula (III), used as such or as amixture with ethyl-2-hexyl nitrate; this effect is measured by applyingthe ASTM-D613 Standard.

[0065] The results are given in Table VI hereafter for a concentrationof 0.1% by weight of alkyl nitrate and 0.025% by weight of additive 1.TABLE VI Cetane number Gain/non-doped Sample (measured) diesel Diesel 148.9 — Diesel 1 + alkyl nitrate 53.5 4.6 Diesel 1 + additive “1” 51.52~6 Diesel 1 + alkyl nitrate + additive “1” 55.0 6.1 Diesel 2 50.9 —Diesel 2 + alkyl nitrate 54.9 4.0 Diesel 2 + additive “1” 53.6 2.7Diesel 2 + alkyl nitrate + additive “1” 56.7 5.8

[0066] The results in this table confirm that the additives according tothe invention do indeed have a cetane number improvement effect, sincethey provide a gain of 2.6 to 2.7. This improvement is higher when theseadditives according to the invention are Introduced into the diesel withanother cetane number improvement additive.

1- Combustible, fuel and/or fuel oil, containing a major part of ahydrocarbon base comprising petrols, middle distillates, syntheticfuels, animal or vegetable oils, esterified or not, and their mixtures,and a minor part, from 50 to 1000 ppm, of at least one multifunctionaladditive enabling fuels to be operable in cold conditions, this additivecomprising copolymers of at least one dicarboxylic compound with atleast one olefin, and whereon are grafted nitrogenous functions and/oresters of general formula (I) hereafter:

wherein: R₁ and R₂, identical or different, are hydrogen or alkylradicals containing from 1 to 20 carbon atoms, R₃ and R₆, identical ordifferent, are hydrogen or alkyl radicals containing from 1 to 30 carbonatoms, where R₃ is selected among alkyl groups containing from 12 to 30carbon atoms when R₆ is hydrogen and vice versa, R₄ and R₅, identical ordifferent, correspond to hydrogen or an alkyl radical containing from 1to 22 carbon atoms, with n and m whole numbers varying between 1 and 50,and X is selected among: i) amine salts of the type

wherein R′₁ and R′₂, identical or different, are selected among alkylgroups containing from 1 to 18 carbon atoms, alkylamines containing from1 to 18 carbon atoms, N-alkylpolyalkylene-amines of formula (II)hereafter:

wherein R′₃ and R′₄, identical or different, are hydrogen or a linear orbranched alkyl group containing from 1 to 22 carbon atoms, and x, y andz whole numbers, x varying between 1 and 6 and y and z varying between 0and 6, and mono- and poly-hydroxylated amines and polyamines; ii) esters—OR′₅, R′₅ selected among alkyl radicals containing from 1 to 30 carbonatoms and N-alkylpolyalkylene-polyamines of formula (II); iii)alkylamines containing from 1 to 44 carbon atoms;N-alkylpolyalkylene-polyamines of formula (II); and when R₆ is hydrogenthe group —NR″₁R″₂ in which R″₁ and R″₂, identical or different, areselected among alkylamines containing from 1 to 22 carbon atoms andN-alkylpolyalkylenepolyamines from the group comprisingN-alkyldiethylene-triamines, N-alkyldipropylene-triamines,N-alkyltriethylene-tetramines, N-alkyltetraethylene-pentamines andN-alkyltetrapropylene-pentamines, or one of R″₁ and R″₂ is an alkylgroup of 12 to 18 carbon atoms and the other is selected amongalkylamines containing from 1 to 22 carbon atoms andN-alkylpolyalkylene-polyamines from the group comprisingN-alkyldiethylene-triamines, N-alkyldipropylene-triamines,N-alkyltriethylene-tetramines, N-alkyltetraethylene-pentamines andN-alkyltetrapropylene-pentamines; the copolymer of formula (I)containing from 45 to 65 mole % of at least one olefin unit and from 55to 35 mole % of at least one dicarboxylic unit. 2- Combustible, fueland/or fuel oil according to claim 1, characterized in that X isselected among: iii) alkylamines containing from 1 to 44 carbon atoms.3- Combustible, fuel and/or fuel oil according to claim 1 or 2,characterized in that the dicarboxylic units are selected amonganhydride type units selected in the group comprising maleic anhydride,citraconic anhydride and fumaric acid, and olefin units selected amonglinear or branched alkenyl units containing from 1 to 30 carbon atoms.4- Combustible, fuel and/or fuel oil according to any of claims 1 to 3,characterized in that the copolymer is selected among the maleicanhydride—octadecene, maleic anhydride—dodecene and maleicanhydride—hexadecene copolymers. 5- Combustible, fuel and/or fuel oilaccording to any of claims 1 to 4, characterized in that R₁ and R₂ areradicals selected among the group comprising dodecyl and octadecylradicals and R₃ is selected among alkyl groups containing from 4 to 20carbon atoms. 6- Combustible, fuel and/or fuel oil according to any ofclaims 1 to 5, characterized in that the copolymer is a compound offormula (III) hereafter:

wherein: R′₁ and R′₂, identical or different, are selected among alkylradicals containing from 12 to 18 carbon atoms, alkyl- andN-alkyl-polyalkylene-polyamines of formula (II) and hydroxylated aminesfrom the group comprising diethanolamine, monoethanolamine,N-butylamine, N-decylethanolamine and N-dodecylethanolamine and theiralkoxylated derivatives; and R₃ is selected among decyl, tetradecyl,hexadecyl, octadecyl and eicosyl radicals. 7- Combustible, fuel and/orfuel oil according to any of claims 1 to 5, characterized in that thecopolymer is a compound of formula (IV) hereafter:

wherein; R″₁ and R″₂, identical or different, are selected among alkylradicals containing from 12 to 18 carbon atoms, alkylamines containingfrom 1 to 22 carbon atoms and N-alkylpolyalkylene-polyamines from thegroup comprising N-alkyldiethylene-triamines,N-alkyldipropylene-triamines, N-alkyltriethylene-tretramines,N-alkyltetraethylene-pentamines andN-alkyltetrapolypropylene-pentamines, and R₃ is selected among decyl,tetradecyl, hexadecyl, octadecyl and eicosyl radicals. 8- Combustible,fuel and/or fuel oil according to any of claims 1 to 5, characterized inthat the copolymer is a compound of formula (IV) hereafter

wherein: —NR″₁ R″₂ is an alkylamine containing from 1 to 44 carbonatoms. and R₃ is selected among decyl, tetradecyl, hexadecyl, octadecyland eicosyl radicals. 9- Combustible, fuel and/or fuel oil according toany of claims 1 to 5, characterized in that the copolymer is a compoundof formula (IV) hereafter:

wherein: R″₁ and R″₂, identical or different, are selected among alkylradicals with 12 to 18 carbon atoms, and R₃ is selected among decyl,tetradecyl, hexadecyl, octadecyl and eicosyl radicals. 10- Combustible,fuel and/or fuel oil according to any of claims 1 to 5, characterized inthat the copolymer is a compound of formula (V) hereafter:

wherein: R′₅ is selected among alkyl radicals containing from 6 to 18carbon atoms and N-alkylpolyalkylene-polyamines of formula (II) from thegroup comprising N-alkyldiethylene-triamines,N-alkyldipropylene-triamines, N-alkyltriethylene-tetramines,N-alkyltetraethylene-pentamines and N-alkyltetrapropylene-pentamines;and R′₃ is selected among decyl, tetradecyl, hexadecyl, octadecyl andeicosyl radicals. 11- Combustible, fuel and/or fuel oil according to anyof claims 1 to 10, characterized in that the alkylamines and theN-alkylpolyalkylene-polyamines of formula (II) are selected among thegroup comprising dibutylamine, didodecylamine, dioctadecylamine,N-alkylethylene-diamines, N-alkylpropylene-diamines,N-alkylbutylene-diamines, N-alkyldiethylene-triamines,N-alkyldipropylene-triamines, N-alkyldibutylene-triamines,N-alkyltriethylene-tetramines, N-alkyltripropylene-tetramines,N-alkyltributylene-tetramines, N-alkyltetraethylene-pentamines,N-alkyltetrapropylene-pentamines and N-alkyltributylene-pentamines withan alkyl radical containing from 12 to 22 carbon atoms, preferablyN-dodecyldipropylene-triamine, N-octadecyldipropylene-triamine,N-octadecyidiethylene-triamine and N-docosyldiethylene-triamine. 12-Combustible, fuel and/or fuel oil according to claim 1, wherein theadditive is a compound of formula (III) hereafter

comprising a copolymer containing maleic anhydride units and octadeceneunits in a molar ratio of 1/1, wherein R₁, R₂, R′₁ and R′₂ are identicaland correspond to a dodecylamine radical. 13- Combustible, fuel and/orfuel oil according to claim 1, characterized in that the additive is acompound of formula (IV) hereafter:

comprising a copolymer containing maleic anhydride units and octadeceneunits in a molar ratio of 1/1, wherein R₁ and R″₁ are hydrogen atoms, R₂is a butyl radical and R″₂ is a dodecyl radical. 14- Combustible, fueland/or fuel oil according to claim 1, wherein the additive is a compoundof formula (V) hereafter:

comprising a copolymer containing maleic anhydride units and octadeceneunits in a molar ratio of 1/1, wherein R₁ is a hydrogen atom, R₂ is anethylamine radical and R′₅ is a hexadecyl radical. 15- Combustible, fueland/or fuel oil according to any of claims 1 to 14, characterized inthat it contains at least one additive selected among filterabilityand/or flow additives, cetane number improvement additives, catalyticcombustion and soot promoters, detergents, lubricating additives,anti-wear additives, anti-foaming additives, anti-corrosion additivesand other additives or additive compositions for improving the cloudpoint, the dispersion and the sedimentation of paraffins.